Side Wall Design

[Trdat]

I will be designing a room soon with my sound system the main entertainment and a room to take in consideration room acoustics. I don't want to delve too much into what a side wall needs as there are anomalies in the room, its not symmetric firstly and I am limited. I will be adding absorption behind the speakers and absorption directly behind the listening position and a general dry wall with parts of the perimeter. And a bad panels for a ceiling panel although I think a bad panel shouldn't be at first reflection points but that is also debatable.

If the side wall is also close but not enough distance for some type of diffusers is there any scattering or possibly a type of diffuser that can be within 2 meters or closer say right up against the sofa on the one side of the LP? Maybe a waveform diffuser...?

 

[Redacted]

Good luck!
Rugs on walls are good.

 

[alex-z]

The lower in frequency your diffuser operates the longer the critical distance.

For a basic 2D diffuser design try QRDude software. You can target a specific cutoff frequency and it tells you the well depths to use and minimum seating distance.

QRDude: Quadratic Residue Diffuser calculator

Free calculator for designing standard and advanced QRD diffusers

www.subwoofer-builder.com

There is nothing inherently wrong with having diffusion at your first reflection points, provided the off-axis response of the speaker matches the on-axis tonality. If your speaker has significant deviations in the horizontal directivity I would opt for absorption.

Is the room being designed from scratch? One of the best approaches is filling the walls with porous absorption and covering it with a durable fabric. You can form highly effective hidden bass traps that way. Then add wooden slates + diffuser panels in front as needed to balance out the decay rates.

 

[Trdat]

The lower in frequency your diffuser operates the longer the critical distance.

But isn't critical distance from the speaker to LP? Or are you talking about the critical distance between the diffuser and LP...?

For a basic 2D diffuser design try QRDude software. You can target a specific cutoff frequency and it tells you the well depths to use and minimum seating distance.

That is not a bad idea however I will be drywalling that particular wall to soundproof the kids room that is behind it and if choose a diffuser with well depths I will really lose space hence why my idea was some type of quadratic wave diffuser.

There is nothing inherently wrong with having diffusion at your first reflection points, provided the off-axis response of the speaker matches the on-axis tonality. If your speaker has significant deviations in the horizontal directivity I would opt for absorption.

Well, my wide dispersion speaker is a DIY design and I don't have any off axis measurements and haven't done any of my own turntable off axis measurements. Perhaps I can stick to absorbtion.

Is the room being designed from scratch? One of the best approaches is filling the walls with porous absorption and covering it with a durable fabric. You can form highly effective hidden bass traps that way. Then add wooden slates + diffuser panels in front as needed to balance out the decay rates.

The room is already designed but I might add drywall to it which gives me some room to move when it comes to adding absorption and slats and I will do what you suggested, with the wall behind the speakers but the walls I want to soundproof the particular one which will end up right beside the LP, if I add drywall and then more absorption and slats I lose a lot of space.

But there are ways around it that I have come up with kind of hybrid designs.

 

[alex-z]

But isn't critical distance from the speaker to LP? Or are you talking about the critical distance between the diffuser and LP...?

That is not a bad idea however I will be drywalling that particular wall to soundproof the kids room that is behind it and if choose a diffuser with well depths I will really lose space hence why my idea was some type of quadratic wave diffuser.

Well, my wide dispersion speaker is a DIY design and I don't have any off axis measurements and haven't done any of my own turntable off axis measurements. Perhaps I can stick to absorbtion.

The room is already designed but I might add drywall to it which gives me some room to move when it comes to adding absorption and slats and I will do what you suggested, with the wall behind the speakers but the walls I want to soundproof the particular one which will end up right beside the LP, if I add drywall and then more absorption and slats I lose a lot of space.

But there are ways around it that I have come up with kind of hybrid designs.

Critical distance applies to any source including diffusers, it is when the direct and reflected sound are equal in level.

You can pick whatever diffuser type you want, the depth of the elements sets the limit on low frequency performance. There is nothing wrong with a thin diffuser if you have a specific high frequency problem but you still need to compliment them with absorption for a balanced decay rate.

Definitely measure your speakers off-axis. A shocking number of models have a crossover designed only for on-axis response and are worth fixing or replacing.

 

[Flaesh]

my wide dispersion speaker is a DIY design and

Both pairs? The white directivity doesn't seem very broad.

 

[dannut]

If the side wall is also close but not enough distance for some type of diffusers is there any scattering or possibly a type of diffuser that can be within 2 meters or closer say right up against the sofa on the one side of the LP? Maybe a waveform diffuser...?

No diffuser is ideal nearfield (lobing), it takes space for the soundfield to stabilize. Your best bet is a curved binary-amplitude device in the nearfield (BAD). Bonus if they have absorption below the scattering/diffusing frequency also. But why not a simple absorber, open bookcase, etc absorbing device instead?